Screw type filling machine



lO Sheets-Sheet l W. R. PETERSON SCREW TYPE FILLING MACHINE Filed Dec. l5, 1948 All@ 24, 1954 w. R. PETERSON 2,687,244

SCREW TYPE FILLING MACHINE Filed Dec. l5, 1948 10 Sheets-Sheet 2 2 I INVENTOR.

WILLlAM- RPETERSON.

BY MWLM ML Ju.

ATTORNEYS,

Allg- 24 1954 w. R. PETERSON SCREW TYPE FILLING MACHINE l0 Sheets-Sheet 3 Filed Dec. l5, 1948 Y6)A P. R im ,M A ww W Aug. 24, 1954 w. R. PETERSON SCREW TYPE FILLING MACHINE 10 Sheets-Sheet 4 Filed Dec. l5, 1948 INVENTOR. WlLLlAM R. PETERSON.

5 ATTORNEYS.

lg- 24, 1954 A w. PETERSON 2,681,244

SCREW TYPE FII-LING MACHINE Filed Dec. l5, 1948 l0 Sheets-Sheet 5 :LLIAM R. PE1-525cm BY ATTORNEYS.

Aug. 24, 1954 w. R. PETERSON scREw TYPE FILLING MACHINE 10 Sheets-Sheet 6 Filed Dec. l5, 1948 INVEI'MTORL R m MH Dm A R. f MWL .L

Aug. 24, 1954 w. R. PETERSON SCREW TYPE FILLING MACHINE Filed Dec. l5, '1948 l0 Sheets-Sheet 7 JNVENTOA m PET ERSON VVILLIAM R ATTORNEYS.

Aug. 24, 1954 w. R. PETERSON scREw TYPE FILLING MACHINE 10 Sheets-Sheet 8 Filed Dec. l5, 1948 i EE-w.

NVENTR. VV: L LlAM R. PETERSON.

BY wahl.,

Aug. 24, 1954 w. R. PETERSON SCREW TYPE FILLING MACHINE 10 Sheets-Sheet 9 Filed Dec. l5, 1948 INVENTOR. WlLLx'AM Ripa-ransom.

BY C! e L ATTORNEYS.

Aug. 24, 1954 w. R. PETERSON SCREW TYPE FILLING MACHINE 10 Sheets-Sheet 10 Filed Dec. l5, 1948 VVILLIAM K PETERSON.

a ATTORNEYS.

Patented Aug. 24, 1,954 f SCREW TYPE FILLING MACHINE William R. Peterson, Oswego, N. Y., assignor to St. Regis Paper Company, New York, N. Y., a corporation of New York Application December 15, 1948, Serial No. 65,395

Claims.

This invention relates to filling machines employing augers or screws for forcing granular or pulveruient material into containers, and more particularly to means for increasing the feeding efficiency of such machines.

The invention in one aspect thereof is constituted by a multi-blade centrifugal impeller used in combination with a filling screw, the centrifugal impeller being adapted for urging material into the spaces between the helical surfaces of the screw to increase the filling efficiency of the latter. Also in combination with the impeller are means for urging material into the spaces between the blades thereof. The filling screw is situated at the bottom of the casing or trough-like device and is in alignment with a nlling tube which is adapted for insertion, for example, into the valve of a valve bag. The lling screw may extend partially into the rilling tube. The blades of the impeller reach down into close proximity with the filling screw and thus into the trough in which the latter is located, whereby material is forced into the screw under the influence of centrifugal force and by a wiping action of the impeller blades. The efficiency of the filling screw and the volume of material which it is capable of moving is increased to a point not heretofore attained and the output of filled containers per hour, with particular reference to light and iiuify material, is increased many fold as compared to the output of conventional or well known apparatus.

Apparatus which have been suggested in the past for increasing the efficiency of a discharge screw or filling screw for a container filling machine have relied upon mere agitation or upon gravity for urging the material into the screw. However, such apparatus in many instances have proved unsatisfactory with certain types cf material, for example of the light fluffy variety, and have been unable to achieve a desirable output of filled containers per unit time.

In the handling of some types of material, particularly of said light and iluify variety or such varities which tend to mass and to cling together, many serious problems arise which prior types of filling apparatus have been incapable or" overcoming. For example, apparatus suggested in the past for packing such special types of materials have been incapable of attaining a desired high output of filled valve bags per hour, and simultaneously with the filling thereof to weigh each charge of material accurately.

According to the present invention, apparatus is provided for greatly increasing the speed at which containers, such as valve bags, can be filled and for eliminating the above-mentioned difficulties.

Various, further and more specic objects, features and advantages of the invention will clearly appear from the detailed description given below taken in connection with the accompanying drawings which form a part of this specification and illustrate by way of example preferred arrangements of apparatus for carrying out the invention. The invention consists in such novel combinations and features of apparatus as may be show and described in connection with the apparatus herein disclosed.

Fig. l is a side elevation illustrating one embodiment of the present invention employed in connection with a valve bag packer;

Fig. 2 is a side elevation of one form of the invention on an enlarged scale with parts broken away and partly in section taken substantially on line 2 2 of Fig. 4;

Fig. 3 is a front elevation of the apparatus shown in Fig. l;

Fig. 4 is a front view of the novel packing means embodying the invention, the view being partly in section and with parts broken away and taken substantially on lines 4 4 of Fig. 2;

Fig. 5 is a front view with parts broken away of a paddle agitator or centrifugal impeller which can be employed in the present invention;

Fig. 6 is a side elevation partly in section and with parts broken away of a second embodiment of the invention;

Fig. 6a is a sectional view taken substantially on line lia- 6a of Fig. 6;

Fig. '7 is a plan View of the agitator mechanism shown in Fig. 6;

Fig. 8 is a front elevation partly in section and with parts broken away of a filling machine illustrating a third embodiment of the present invention;

Fig. 9 is a side elevation also partly in section and with parts broken away of the apparatus illustrated in Fig. 8;

Fig. 10 is a schematic perspective representation of the novel filling means and certain of its control devices employed in the embodiment of Fig. 8;

Fig. ll is a view in greater detail of certain of the parts illustrated in Fig. 8, with special reference to the dust collecting and removal means;

Fig. 12 is an enlarged detailed view partly in section and with parts broken away of the bag filling tube, the feed gate and certain related parts as employed in the embodiment of Fig, 8;

Fig. 13 illustrates one form of feed gate latohing arrangement which can be employed in the present invention;

Fig. 14 is a schematic representation of a wiring diagram which can be employed for interconnesting the electrically operable parts of the invention;

Figs. 14a to 14d, inclusive, show the wiring diagram of Fig. 14 and illustrate certain electrical circuits which are made during the operation of the apparatus, said circuits being shown in heavy mes;

Fig. 15 is a side view partly in section and with parts broken away of a modification of the invention;

Fig. 16 is a front View of the parts shown in Fig. 15 with certain parts omitted for clarity; and

Figs. 17 and 18 are respectively sectional side and front views of still another modification of the invention.

Referring to the drawings in further details, one embodiment of the present invention is illustrated in Figs. 1 4, inclusive, and is constituted by a novel filling screw device adapted for use, for example, with pre-weighed charges of material or in apparatus where the filling screw is controlled by mechanism such as a timing device which operates same during predetermined periods for filling a valve bag.

A lling screw 20 is provided having a central shaft 2i which is mounted for rotation in a suitable journal 22 and situated with a portion thereof within a trough 23 and another portion thereof within a filling tube 24. fined as an elongated channel-like casing having a rounded bottom, there being suitable enclosures at opposite extremities of such trough. One of such enclosures is provided with an opening through which the filling screw urges material. The lling screw 2e is adapted for rotation at the bottom of the trough 23, the width of which, as shown in Fig. 4, and for a purpose to appear below, is substantially equal to the outer diameter of screw 20. The outer diameter of the screw portion within the filling tube 24 is substantially equal to the inner diameter of said tube, there being suitable clearance to permit free rotation of the screw. In the form shown,

the pitch and diameter of filling screw 2t! are constant and the latter terminates preferably just short of a throat 24a of the filling tube.

In order greatly to increase the efficiency of the lling screw, that is, its ability to move material out of the trough 23 and through the tube 24, novel means are provided for forcing material down into the ights of the filling screw oomprising a multi-blade centrifugal impeller, as at 25, having blades or paddles 25 which, as shown in Fig. 4, are of constant width from the hub to the extremities thereof. The blades 26 sweep down into close proximity with the filling screw 20 and force material therein, the direction of rotation of the impeller being counterclockwise as viewed in Fig. 2, whereby material is forced into the screw and toward a trough outlet 23a which constitutes the entrance to the filling tube 24. The ability of the impeller '25 to force material down into screw 20 is increased by making the width of the blades 26 substantially equal to but slightly less than the width of trough 23, as in Fig. 4. However, the invention is not limited thereto.

The impeller 25 is mounted upon a rotatable shaft 2l which preferably is in a plane perpen- Trough 23 is dedicular to the axis of lling screw shaft 2 I. Thus the impeller plane of rotation, namely, the plane through the center of the impeller and perpendicular to itsaxis of rotation, substantially contains the axis of rotation of the filling screw 20.

The blades 26 of the impeller 25 preferably extend outwardly along axes which are non-radially disposed with respect to the shaft upon which they are mounted. That is, the inner ends of the longitudinal axes of such blades are spaced from the axis of rotation, for example, the axis of shaft 2'( (Fig. 2). Such inner ends of the longitudinal axes refers to the portion thereof closest to the shaft 2l. The blades 26 have substantially plane forward surfaces which initially engage the material.y Secured to the outer extremities of such forward surfaces of the blades are so-called impeller tip members which assist the impeller blades in effecting a troweling action of the material down into the flights of the filling screw. Thus the aforementioned nonradial disposition of the blades 25 is substantially tangential to the hub upon Which they are mounted and aids in urging the material outwardly, the tip members 25a assisting in lling the flights of the filling screw 20.

Subsidiary impeller means are provided for feeding material from either side of the rotatable impeller 25 into the spaces between the blades thereof comprising, for example, packer screws or auxiliary screws 28 and 28 located respectively on the left and right sides thereof, as viewed in Fig. 4, said packer screws preferably being coaxial with the impeller and mounted upon the same shaft therewith. In order to assist in providing a positive feed to the impeller 25, the packer screws 28 are mounted at the bottom of troughs 30 and 3|, respectively, said troughs comprising `the lower surfaces of a hopper 32 into which material is delivered to be fed into a valve bag as at 33 shown in filling relation with said lling tube 24. The ends of troughs 30, 3l adjacent the impeller 25 are open.

With reference to the relative rotational velocities of impeller shaft 2'! and the filling screw 2li,

these velocities can be expressed in terms of the frequency of blade impulses and the R. P. M. of the filler screw. For example, as shown in Fig. 2, the impeller 25 is provided with four blades. Consequently when the shaft 2l rotates at 2.00 R. P. M. there will be 800 blade impulses per minute adjacent the lling screw. Thus if it is desired for a blade to deliver material to the screw for each revolution of the latter, impeller shaft 27 should rotate at 200 R. P. M. and screw 2! at R. P. M. thereby effecting a ratio of blade impulses to screw speed of one to one. In certain instances, for example, 4lwith material such as flour mixes containing shortening, it has been found desirable to increase the R. P. M.'of the filling screw to a point approximately twice the frequency of the paddle impulses.

As shown in Fig. l, a common power source comprising a motor as at 34 is employed for driving both the lling screw 2li and the impeller shaft 21. A belt 35 interconnects a suitable pulley upon the shaft of motor 34 with a pulley upon screw shaft 2| of the filler screw 22. The motor 34 may transmit its power to the impeller shaft 2l through the intermediary of a suitable reduction gear 36 which can receive power by a conventional belt connection with motor 34, such as a belt 36a (Fig. 3) passing over pulleys 31 and 38. The output shaft of the reduction gear 36 is provided with a suitable wheel, such as a rotation of the impeller is substantially constant. However, it is possible to employ a type of impeller as illustrated in Fig. 5 having blades which are not of constant width, but which comprise arms 42 of relatively small width measured from the hub to arm extremity and each of which is provided, for example, with a relatively large paddle surface at the extremity thereof. As shown in Fig. 5, each blade is constituted by said relatively slender arm 42 extending from the impeller hub, and a paddle 43 is mounted at the extremity of each arm. Suitable right and left auxiliary or packer screws, of course, may be mounted coaxially with and upon the same shaft with such an impeller, and driven at the same speed therewith. The length of each paddle 43 preferably is approximately equal to the diameter of the filling screw 26 and to the width of trough 23 whereby the paddles cooperate with the trough sides to direct and force material into the filling screw.

In the embodiment illustrated in Figs. 6, 6a and '7, the structure is somewhat similar to the embodiment previously described with the exception that the right and lefthand packer screws do not operate in individual troughs but instead such troughs are eliminated and a supplementary impeller-packer device is employed beneath each such screw. Such supplementary impellerpacker devices thus are rlocated one on each side of the main impeller 25 and are positioned to force material into the spaces between the blades of said main impeller whereby the packer screws 23, 29 are assisted in their task. Each supplementary impeller-packer device comprises, in the form shown, a rotatable supplementary shaft which is preferably parallel to the shaft of the filling screw 29. Upon each such supplementary shaft is a small supplementary impeller to which material is urged by a feeder screw. Preferably the feeder screws and supplementary impellers are respectively located in diagonally opposed positions.

As shown in Fig. 6a, the filling screw 20 is rotatable within a suitable trough 44 in a manner substantially similar to that shown in Fig. 4. However, trough 44 is broadened in cross-section, as compared to trough 23, above the filling screw 26 in order to accommodate supplementary impeller-packer mechanisms 45 and 46, respectively upon the right and lefthand sides thereof and above said filler screw 20. Mechanism 46 is constituted, for example, by a screw 41 which urges material toward an impeller 48. impeller 48 rotate preferably in a counterclockwise direction (Fig. 6a.) and the latter urges material toward the main impeller which, for example, is of the type shown in Fig. 5. Thus it will be seen that the impeller 48 urges material toward and between the downwardly moving paddles 43 of the main impeller thereby assisting in filling the main impeller .and the main filling screw 20.

The other supplementary packer 45 is similar Screw 41 and.

to mechanism 46. However, its disposition is reversed in that an impeller 49 is located diagonally opposite impeller 49 (Fig. 7). The impeller 49 is mounted upon a suitable shaft parallel to and above the screw 20. A feeder screw 50 also is mounted upon said shaft which urges material toward the said impeller 49. The direction of rotation of impeller 49 and screw 50 is clockwise as viewed in Fig. 6a whereby the impeller 49 urges material toward the main impeller 42.

The action of the impellers 48, 49, in addition to urging material toward the main impeller 25,

' also may force some material by Virtue of centrifugal force toward and down into the ller screw 29.

In the embodiment of Figs. 6, 6a and 7 right and lefthand packer screws 28 and 29 preferably are mounted on either side of the main impeller 42 in a manner analogous to that shown in Fig. 4. Suitable means (not shown) are provided for rotating the supplementary packers 45 and 46 in a desired speed ratio to the main impeller 25 and the filler screw 20.

A consideration of Fig. 6a indicates that the lower portion of the trough 44 in cross-section is substantially in the shape of a V with the filling screw 26 rotating in the bottom thereof. Below the region where the upper extremities of the sides of the V join the vertical sides of a hopper 44a, there are respectively situated the abovedescribed supplementary impeller-packers 45 and 46, the sides of the V being rounded as at 44h to accommodate such packers.

The embodiments o1" the invention previously described have been adapted for use, for example, in the packing of pre-weighed charges or in the packing of charges by timing the period of operation of the lling screw 20. In both of these cases, simultaneous filling and weighing of the container does not occur and consequently it is not necessary to have a movable scale and a socalled divorce line in the filling tube in order to permit a weighing movement of part of such tube relative to a stationary part thereof.

In the embodiment of the invention illustrated in Figs. 8-14, inclusive, a filling screw and centrifugal impeller means are employed which are somewhat similar to the embodiment shown in Fig. 4 with the exception, for example, that such screw and impeller are employed in combination with a packer which is adapted for simultaneously filling and weighing containers such as valve bags.

Referring to Figs. 8, 9 and l0, the lling screw and impeller mechanism, which is similar in certain respects to the embodiment in Fig. 4, is constituted by a filling screw 55 which is located in the bottom of a filling screw trough 56. Filling screw 55 is provided with a central shaft 51 which is journaled for angular movement in a suitable bearing 58 and which extends rearwardly, as viewed in Fig. 9, for interconnection to an electric motor 59 by means of belts 60 which opera-te over conventional pulleys 6I and 62, respectively, upon the shaft 51 and the shaft of motor 59. A second bearing or journal can be provided for shaft 51 adjacent pulley 6|. A rotating impeller with cooperating packer or side screws is employed which is preferably identical with that shown in Figs. 4 and 5 and is constituted by a centrifugal impeller 63 mounted upon a shaft 64, the latter being above and extending transversely of the filling screw shaft 51. Mounted upon either side of the impeller 63 are auxiliary packer screws 65 and 66 (Fig. 8) respectively on theleft and right thereof. Packer screws 65, 66 preferably are mounted upon the shaft 66, the latter being operatively connected to the electric motor 5S through the intermediary of a suitable reduction gear 6l in a well known manner. For eX- ample, a pulley 58 upon the shaft of motor 53 is drivably connected by means of a belt SS to an input pulley 1U of the reduction gear 61. The impeller sha-ft 64 is interconnected to an output sprocket wheel H of said reduction gear by means of a conventional sprocket chain 12 which passes over a suitable sprocket wheel 'i3 keyed to the impeller shaft 64.

If desired, means (not shown) can be provided for adjusting the reduction ratio of the reduction gear 61.

The right and lefthand packer screws 65 and t6 are rotatable within and at the bottom of their respective troughs 14 and 15 in a manner identical to that shown in Fig. 4.

In order to provide for simultaneous weighing and filling of a valve bag, a. suitable scale 'i6 (Fig. 9) is provided which supports a portion of a bag filling tube 'i1 which is adapted for undergoing weighing movement therewith. As shown in Fig. 9, the scale 16 is constituted by a conventional scale beam 18 which rests upon a suitable knife edge 'i9 and has secured thereto upon one side of said knife edge a weight 80. Suspended on the scale beam 18 upon the other side of said knife l edge is a so-called weighing frame or bag frame 8| upon which is mounted said filling tube portion 'Ii in a manner to appear more fully hereinafter. Frame 8l is supported by the beam '18 preferably through the intermediary of a conventional knife edge S2 and cushion S3.

In order to insure a parallelogram vertical movement of the frame 8l, a conventional check rod 8A is pivotally associated with the lower extremity of said frame.

A bag clamp handle 85 is pivotally mounted upon the frame 8i and adapted for opening and closing a bag clamp 86 in a well known manner. For example, the bag clamp 8G is pivotally mounted at 8i and is urged upwardly toward an open position by means of a spring 88 which is secured at one extremity to an arm 85a upon the handle 3d. The latter is pivotally mounted intermediate the extremities thereof and provided with a suitable roller 89 which is adapted for engaging and closing the clamp 86 when the handle 85 is pushed in a counter-clockwise direction (Fig. 9).

A bag chair 9S is associated with the lower portion of frame 8i and is adapted for adjustment in a vertical direction by means, for exai. ple, of a vertical rod 9| which supports said chair, and is provided with a serrated surface 92 which cooperates in a well known manner with a detent S3. An eccentric cam 93a resiliently urges serrations 92 against detent 93 by means of a spring 93h.

I have found novel means for increasing the compression of material into the flights of the lling screw whereby a more forceful and positive feed into said screw is obtained which effects a substantial improvement over the performance of the embodiment shown in Figs. 1 4, inclusive, with particular reference to such light materials as diatomaceous earth. Such novel means are indicated as in Figs. 9 and l0 and are constituted by a stationary iilling screw shroud Tia, which protrudes inwardly into the filling tube trough 5t partially to cover the filling screw 55. The shroud 11a. constitutes a part of the filling tube '17a to permit the passage of material.

17 and is normally in alignment therewith and assists in delivering material thereto in a more eflicient manner. The shroud 'Via extends into the filling tube trough 56 preferably toa point approximately beneath the center line of the impeller shaft 65. Thus the opening through which material can be urged into the filling screw is considerably reduced but with advantageous results. The termination of the shroud 11a at a point substantially beneath the center line of shaft Gli occurs approximately at the region where the downward thrust of each impeller blade changes direction toward the horizontal. Thus any tendency of the material in the filling screw to boil up and to recirculate in the region near the outlet of the trough 5tl is inhibited. A considerable resistance to the ow of material may occur within the filling tube portion 11 which, under normal circumstances, might produce such boiling or recirculation.

In order to reduce such resistance to the flow of material in the iilling tube il, and to aid in preventing clogging, the tube preferably is formed with a. so-called reversed taper, that is, it is slightly larger at the outlet thereof and at the inlet. Such a taper, for example, can be one degree from inlet to outlet.

Filling screw 5.5 terminates approximately at the divorce line between tube Ti' and shroud 'ila and preferably just short thereof in such a manner that the movable tube T! can undergo weighing movement without obstruction.

When a complete charge has been fed into a bag, a weighing movement of the scale 18 takes place which is adapted for tripping a latch device and thereby closing a slidable feed cut-off gate 94 (Figs. 9, l() and l1). Gate 9d, as shown in Fig. 11, is provided with an opening 94a` which can move into register with the outlet of shroud Suitable guide plates 95 and 96 are provided for directing the sliding movement of said gate.

A gate control rod Si is attached, for example, to the lower portion of the gate S4, and is adapted for sliding movement through a guide bracket 93. A coil spring 99 is interposed between the bracket et and the gate Sli for urging the latter toward a closed position. Latching means for holding the gate gli open are shown in Fig. 10 and constitute, for example, a latch dise itil secured to the lower extremity of rod 9i and which is adapted for cooperation with a latch IQ! (Fig. 13). The latter is angularly shiftable upon a shaft 102 and is governed in a manner which will appear hereinafter whereby the latch is tripped and the gate is closed when a desired weight of charge has been reached.

In View of the use of shroud Tia, it is desirable to arrest immediately the angular motion of the lling screw 55 when such desired weight has been reached and the gate et is closed, whereby a coasting of the iilling screw and excessive preseures upon the gate Sii are avoided. A brake H13 (Fig. 10) is provided for this purpose which can be of any desired conventional type and which, in the form shown, is constituted by a pair of pivotally mounted brake arms i8@ and m5 having respective braking surfaces which engage a brake drum |96 mounted upon the filling screw shaft 51.

The brake 63 is preferably operatively connected to the gate latch i, lili by suitable linkage whereby the brake is applied at the same time that said latch is tripped and the gate 94 is closed. `Such operative interconnection, as shown in Fig. 10, is constituted by a brake lever |01 which, by means of a brake rod |08, is angularly shiftable with the latch shaft |02 by virtue of an arm |09 which is secured to shaft |02 and is pivotally connected at I I with said rod |08.

Thus it is apparent that by angularly shifting the latch shaft |02 in a clockwise direction (Fig. l0), the brake |03 will be applied and the latch |0I will be released to close gate 94. A solenoid I is provided for this purpose which may be energized in response to weighing movement of the scale 'I6 in a manner to be explained below, and which can angularly shift the latch shaft |02 by means of an interconnecting arm IIa. (Fig. It is desirable to have the shaft |08 divided into yieldingly telescoping portions |08a and |0819 which are normally urged apart by means of a coil spring II2 which surrounds the former and acts against suitable collars on said portions. When the solenoid I I is energized, the brake |03 is yieldingly engaged and latch |0| is positively withdrawn from la-tching engagement with disc |00. When the solenoid I| is deenergized. gravity is effective to disengage brake |03 and re-position latch |0| in position to engage the disc |00.

Manually operable means are provided for opening the gate 94 and initiating the operation of the apparatus comprising a handle |I3- which is pivoted as at I I4 and adapted for engaging a roller ||5 (Figs. 9, 11 and 12) attached to said gate 90, the engagement occurring when handle ||3 is shifted downwardly. When said handle is shifted from the position shown in solid lines in Fig. l0 to the position shown in the broken lines, the gate 94 is latched in an open position, and a normally open limit switch H6 (Fig. 10) is closed momentarily to start the machine. A switch arm I|3a is secured to handle I3 for engaging switch ||6. After said handle is manually7 released, a coil spring |I'| will return same to its normal position. The closing of the limit switch ||F actuates the motor 59, as will be explained below. When a desired weight of material has been fed into a bag upon the filling tube '11, weighing movement occurs, and the lefthand extremity of the scale beam 'I8 (Fig, 9) will move upwardly to open a normally closed switch |I8 whereby the solenoid I I I is energized, the brake |03 is immediately applied, latch I0| is tripped, gate 94 is closed, and the motor 59 deenergized.

In order to avoid overheating of the solenoid it is desirable to adapt same for energization only when the bag clamp 86 is closed. Thus during periods of idleness and during the period between the application of bags upon the tube TI, the solenoid Will be deenergized. In order to accomplish this a switch I 9 (Fig. 12), which can be a double throw type, is operatively associated with the handle v85 by means of a linkage |20 in such a manner that when the bag clamp is open, an electric circuit to the solenoid is interrupted, and when the bag clamp is closed, said solenoid electric circuit is interrupted until the desired weight of material is reached in the container.

Anovel spill chute |2| (Fig. 9) is provided which is pivoted at the lower extremity thereof as at |22 upon the movable frame 8| and which empties into a fixedly mounted spill trough I 24 (Figs. 9 and 11). The pivotal mount of the spill chute |2I is positioned in such a manner that gravity normally urges the chute outwardly in a clockwise direction. An arm |25 is provided for limiting such outward angular movement to a point where the tip of the chute, at its outermost position, is to the right of a throat 'Il'b of the filling tube TI as viewed in Fig. 9. Thus, when a bag is removed from the tube TT, the spill chute |2'I is pulled by gravity to the position shown in Fig. 9 and is adapted for catching any spill from said throat Tlb.

A dust suction hood |26 (Figs, 9 and l2) is positioned between the movable frame 3| and the fixed support for the apparatus and is mounted upon the latter. Such hood is adapted for surrounding the so-called divorce line between the movable filling tube 'Il and the fixed guide plate 96 whereby any spill at the divorce line is either sucked away or directed to the trough |24.

The suction hood |26 is fixed, being secured at |26a to the xed support or framework of the apparatus. The filling tube 'I1 is, of course, movable and extends through said hood. Thus the latter must be conformed so as not to obstruct movement of the filling tube. A removable panel |261) is provided at the front of the hood |26 or at the right thereof as viewed in Fig. l2. Panel |261) in turn is provided with an outwardly extending ilanged portion |21 having a slot I2'|a through which filling tube TI extends and in which it can move vertically.

The movable filling tube TI is secured to the weighing frame 8| by means of a ange |28 (Fig. 12),the latter being spaced preferably a small distance from the inner extremity of said tube, thereby forming a shoulder for supporting a flexible washer |29 preferably of a material such as felt which is movable with the lling tube and is in frictional contact with the front surface of the guide plate 96, whereby an adequate movable seal is obtained between a stationary opening 96a in guide plate 95 and the movable entrance into the filling tube 11. Opening 96a, is, of course, in alignment with the outlet of tube or shroud 71a.

Thus any material which escapes past the seal between washer |29 and guide plate 90 will be carried away by the dust suction hood 26 which is in communication with a suitable suction device. Any heavy material which cannot be carried away through the hood will fall into the trough |24 were it can be carried away, for example, by a waste removal screw |30 (Figs. 8 and 11) which is mounted for rotation in the bottom of said trough, the latter being provided with an outlet as at I3| preferably at one side of the machine. A waste container can be placed beneath the outlet |3I. The waste removal screw |30 is operatively connected to the motor 59, for example, by means of a belt |32 which connects the shaft of the reduction gear E1 with the shaft of said screw, said belt passing over conventional pulleys.

The filling tube portion Ha in one form of this invention need not protrude into the filling screw trough 56 but may extend outwardly therefrom and be attached to the discharge outlet of said trough. In such form of the apparatus the operation thereof will be similar to the embodiment of Figs. 1-4. However, one of the advantages of the inwardly protruding filling tube portion is to shorten the length of the scale beam 13. If the filling tube portion Ha protruded externally from the filling screw trough 56, it would be necessary to increase the length of scale beam 18 whereby the divorce line between the movable filling tube portion TI and the fixed portion 11a will be properly positioned.

A preferred means for electrically associating the above-described switches H6, ||8, I|9 with the motor 59 and the solenoid is indicated in Fig. le and includes a so-called magnetic starter |33 for the motor 5i! which is under the influence of said switches, as will appear below. The motor 59, for example, is of a three-phase variety and is connectable to a three-phase power source having electrical power leads i3d, i3d and |36. Three input terminals of the motor 59 are respectively electrically connected to three electrical switch terminals. |31, |38 and |39 by means of leads 49, 'itl and |42. A three-pole movable switch arm |43 is provided which can be, for example, axially shifted simultaneously to connect said three switch terminals with respective of said power lines. Normally the threepole switch arm is held in an open position by means, for example, of a suitable spring |45. The three switch arms are indicated as at |l3a, It-ib, and illc. A fourth switch arm |45 is mounted therewith for completing a so-called magnetic interlock circuit, as will be explained hereinafter. The interlock switch arm |45 is adapted for interconnecting interlock terminals ila |452).

The switch |33 can be closed by overcoming the pressure of spring lcd by means of a starter coil |46. aAn electric circuit through the starter coil |45 is effected by means of a lead Mil which is connected, for example, across leads Hifi and |36. Interposed in the lead is a start-stop switch |48 and the above-described switch H6 which is under the inuence of the handle |53. Thus when the handle H3 is thrust downwardly to its lowermost position, the normally open switch is closed to complete the starter coil circuit and thus to close the motor switch |33. Lead lill also interconnects the above-mentioned terminals i555@ with the power line |36 in order that an interlock circuit can be formed for holding switch arms |63 in a closed position after the switch llt is opened. Since the switch il@ is only momentarily closed, an interlock circuit is needed and is formed by means of a lead Uit which interconnects the interlock terminal |1115?) to a point intermediate the switch il@ and the start-stop switch |438. interposed in the lead |49 is the above-described scale operated switch IIB which thus is adapted for breaking said interlock circuit, deenergizing the starter coil |45 and opening the starter switch when a desired weight of a charge has been reached.

The switch H9, which is under the influence of the bag clamp 85, is associated with the apparatus in such a manner that when the packer is idle, that is, when the bag clamp is open and the motor 59 is arrested, the solenoid Hi is deenergized. Thus the danger of burning out of this solenoid during long periods of idleness is avoided. The solenoid is energized only when the bag clamp is closed (with motor idle) and before weighing movement has taken place. Solenoid hum is conned to such latter period.

The electrical connection of the solenoid Hl into the circuit of the apparatus is as follows: A solenoid relay |il governs solenoid i in conjunction with the above-described bag clamp electrical switch i i@ in such a manner that when the bag clamp and the magnetic starter |33 are open, said solenoid is deenergized. Also when. the bag clamp is closed and the magnetic starter |33 also is closed to energize motor 59, the solenoid is deenergized. However, said solenoid is energized whenever the magnetic starter is open and simultaneously therewith the bag clamp is closed, which situation will occur when weighand ing movement oiscale it takes place, as will appear below.

The relay |5|l may be of conventional type and can comprise, for example, a pair of normally closed electrical contacts |5| and |52 which are under the influence of a relay coil |53 in a well known manner. The solenoid is connected, for example, across power leads |355, |35 by means of leads |54 and |55, respectively, the normally closed relay contacts il, |52, respectively, being interposed in the leads |54, Iti,

The relay coil |53, by means of the bag clamp electrical switch IIS, is adapted for being connected (l) across the power leads |34, |35 when the bag clamp is in the open position whereby the relay contacts |5I, |52 are maintained also in an open position and vthus the solenoid is deenergized; and (2) across the power lead |36 and the motor lead lill (at terminal |38) when the bag clamp is closed, whereby the relay coil |53 is energized when the magnetic starter is closed and the bag clamp is closed.

The bag clamp switch H9 thus is adapted for moving into electrical connection with either the power lead |35 or the motor lead IM. Switch H51 for this purpose is provided with a switch arm Htc which is adapted for moving into Contact either with an electrical lead |58 connected to power lead |35, or with a lead |51 connected to the motor lead mi. The switch Htc is connected to one extremity of relay coil |53 by a lead E58, the other extremity of coil |53 being connected to lead |54 at a point intermediate contact ibi and the power line 36.

ln operation of the embodiment of Figs. 1 4, inclusive, a charge such as a pre-weighed charge is delivered into the hopper 32 and the portion thereof which is substantially above the centrifugal propeller 25 falls in between the blades thereof and is immediately forced down into the flights of the filling screw 20. The blades 2S (or 42, 3) with the assistance of gravity hurl the material into the spaces between the screw surfaces of the lling screw. The packer or auxiliary screws 28, 2t urge material laterally into the spaces between the rapidly rotating blades of said propeller whereby a positive and forceful feed thereto is continuously maintained until the material in the troughs 3B, 3| has been exhausted. The trough 23 in which the iilling screw 2t rotates assists in guiding the material directly into the filling screw, there being no lateral passage through which such material can escape. Thus the sides of said trough 23 cooperate with the rotating impeller to direct the discharge from the latter directly into the filling screw. The troughs 39, 3| act in a somewhat similar manner in that they guide material which has fallen therein directly into their respective packer screws by which the material is immediately urged into the spaces between the rotating impeller blades.

In operation of the embodiment of Figs. 6, 6a and '2, the main centrifugal propeller 25 is fed not only by the auxiliary screws 28, 29 but also by supplementary packer devices 45, i6 all of which urge material into the spaces between the rotating impeller blades. Furthermore the supplementary impellers 58, i9 will assist in feeding the packer screws 28, 29 respectively thereby increasing the eiiiciency of the structure.

In operation of the embodiment of Figs. 8 to 14, inclusive, the following conditions exist at the outset:

(l) The magnetic starter |33 is open, that is, the starter contacts |43 are in the position shown in Fig. 14a. Such contacts |43 are open because a circuit for the starter coil |46 is open and the spring |44 is able to hold said starter contacts open. rIhe starter coil is connected electrically across the leads |34 and |36 through the intermediary of the above-mentioned start-stop switch |48, and the switch ||5 which is closable by the handle I3.

(2) rlhe bag clamp 85 is open and switch arm ||9a is in its uppermost position (Fig. 14a). Thus an electric circuit is completed, for relay coil |53, across the power leads |34, |35, as indicated in heavy lines in Fig. 14a. Solenoid is deenergized.

(3) Because of the deenergized condition of solenoid I the filling screw brake |03 is released and the gate latch device |00, under the action of gravity, is in a latchable condition, that is, the latch |0| is in position for engaging the latch disc |00.

(4) The gate 94 (Figs. 9 and 10) is closed under the influence of the coil spring 90.

(5) The switch |6 is open, as is normally the case unless held closed by the handle ||3.

(6) 'I'he scale switch ||8 is closed, as is normally the case.

A quantity of material to be filled into a valve bag is delivered into the hopper above the troughs 14, and the filling tube 11 is inserted intro a valve of a bag. Thereafter the bag clamp handle 85 is pushed in a counter-clockwise direction to the position shown in Fig. 9, whereupon the bag clamp 86 clamps the bag upon the tube This movement of the bag clamp handle 85 shifts the switch arm ||9a from the position shown in Fig. 14a to that shown in Fig. 14h, namely, from a clamp open to a clamp closed position. This has the effect of deenergizing the relay coil |53 which momentarily creates the circuit indicated in heavy lines in Fig. 14h. The momentary completion of the latter circuit is of no significance but is a mere peculiarity of this particular overall electrical circuit. The circuit shown in heavy lines in Fig. 14h continues only until the handle 3 is thrust downwardly to open gate 04 and start motor 59, as will appear below.

Referring to Figs. 10 and 14C, the handle |3 thereafter is thrust downwardly tol the position shown in broken lines in Fig. l0 and then is released to turn to its normal position, as shown in solid lines. This has the following results:

(l) The cut-off gate 94 is latched open.

(2) The normally open switch ||6 is momentarily closed because of its engagement with the arm ||3a upon handle ||3.

(3) The momentary closing of switch serves to complete the circuit of starter coil |46 whereby spring |44 is overcome and the starter switch arms |43@ |4319, |430 are thrust toa closed position. The closing of said switch arms provides a direct interconnection between the three power leads and the three motor leads, as above described. Moreover, the movement of the member |43 to a closed position carries with it the so-called interlock member |45 which maintains the electrical circuit of the starter coil |45 after the switch ||6 is again opened and in its normal position. Such starter coil circuit is indicated in heavy lines at A in Fig. 14e.

(4) The closing of the starter contacts or switch arms |43 has two effects, namely, the energization of motor 59 and the deenergization of solenoid Thus the momentary completion of the solenoid circuit, as illustrated in Fig. 14h, is terminated by virtue of the closing of the magnetic starter and immediately solenoid relay coil |53 is energized by completion of the circuit therefor across power line |34 and contact |38 as shown in heavy lines at B in Fig. 14o.

(5) The motor 59 thus starts simultaneously with the release of the brake |03, the latter having been momentarily applied during the completion of the circuit shown in heavy lines in Fig. 1417.

(6.) The filling screw 51 and the centrifugal propeller, together with the packer screws associated therewith, are actuated whereby the material in the troughs 74, 15 and above the centrifugal propeller 03 is fed into the screw 55 and into the valve bag. The packer screws 65, 66 urge material toward the centrifugal propeller 03 and into the spaces between the blades thereof, whereby the latter forcefully and positively urge material down into the spaces between the eX- posed filling screw surfaces, that is, the material is urged into that part of the filling screw which is not covered by the inwardly protruding filling tube portion Tia. The filling tube portion 'Ha terminates substantially beneath the center line of the shaft B4 of the centrifugal propeller whereby full advantage is taken of the downward thrust of each of the blades of said propeller and thus material which is urged into the spaces between the filling screw surfaces will not tend to be carried away by the forward and upward motion of the impeller blades, as viewed in Fig. 9. I have found that an advantageous ratio of propellel` blade impulses (which act to force material into the screw) to the angular velocity of the filling screw to be approximately 800 to 1800 when the material used is, for example, diatomaceous earth or silene.

When the desired weight of material is reached in the valve bag, a weighing movement of scale beam 7B takes place whereby the lefthand extremity thereof (Fig. 9) moves upwardly to open the normally closed switch IIS, as shown in Fig. 14d, whereby the so-called interlock circuit for the magnetic starter is broken and the spring |44 urges the starter contacts to their open position.

When said weighing movement takes place, the gate 94 is immediateLy closed and the motion of the filling screw 55 is simultaneously arrested. These two things take place simultaneously by virtue of the energize-tion of solenoid immediately upon the opening of the magnetic starter |33. The opening of said starter breaks the circuit of the solenoid relay coil |53 whereby the solenoid relay contacts |5I, |52 are closed and the solenoid circuit, as shown in heavy lines in Fig. 1403, is completed. The energization of the solenoid accomplishes simultaneously (a) the applying of the brake |03 through the above-described linkage |0|, |08 and |09; and (b) the 'tripping of the gate latch |0| by angularly shifting its shaft |02, and the closing of gate 94.

Thereafter the bag clamp is opened, switch ||9 reverts to its position, as shown in Fig. 14a, and the circuit therein shown in heavy lines is recompleted whereby the solenoid is again deenergized. Then, of course, the filled bag is discharged from the apparatus.

A modification of the invention is illustrated in Figs. 15 and 16 which is somewhat similar to the parts shown in Figs. ll and 12, with the distinction that the filling screw, instead of being terminated just short of the divorce line, that is, short of the gate 94 as in said figures, extends into the outer portion of the filling tube 'Il past the divorce line. The portion which extends beyond the divorce line is indicated generally at 55a, and is of slightly smaller diameter than the portion of the filling screw 55 which is to the left of said divorce line. The reason for this is to permit a free weighing movement of the filling spout 'Vl through a predetermined distance withoutengagement with the filling screw. The iilling screw 55, 55a, of course, is unable to move vertically to accommodate weighing movement of the tube 1l, and consequently, there must be a reduction in the diameter of the portion 55a to accommodate such movement.

A ga 94h is employed in the modification of Fig. 15 which is similar to gate 94 of Fig. 12 with the exception that it is slotted as at lille to accom-y modate shaft 51 of the filling screw when the gate is moved to a closed position as in Fig. 16. The flights or screw surfaces of said screw are interrupted or discontinued for a short distance on shaft 5l as at 55e in order to permit the slotted gate 94h to move upwardly whereby shaft 5l enters slotl 94e. The interruption at 55e of the screw surfaces occurs intermediate the adjacent extremities of the screw portions 55, 55d at a point which is in alignment with the divorce line. Y

The lling screw 55a and the gate glib, are

V associated with the remainder of the apparatus precisely as described above in connection with the embodiment of Figs. 8-14, inclusive.

rihe modification of Fig. is important because it permits a more forceful urging of material through the filling spout and into the valve bag and assists in reducing the filling time by overcoming any frictional or other resistances which might be encountered within the portion of the filling tube which undergoes weighing movement. makes it unnecessary to have a so-called reverse taper upon the portion of the filling tube il, as shown in Fig. 12, in order to prevent a clogging of the filling tube. The possibility of a clogging of filling tube portion 'Il (Fig. l5), is nulliiied by virtue of the filling screw portion 55a.

Another modification of the present invention is shown in Figs. 17 and 18, in which a centrifugal impeller, shown in the above modifications at and 63, is omitted, and the auxiliary or packer screws are lowered so that they are capable of feeding directly into the main filling screw.

1 have determined that this latter modification of the invention can achieve a lower filling time `with certain types of material, such as soda ash, than has ever before been obtained, and

Vthus that the output of filled bags per hour can be increased a sustantial amount.

lt has been found desirable, under some circumstances, so to eliminate the centrifugal impeler because it may tend to throw the material upward. Where a substantial head of material is employed above a centrifugal impeller, the tendency to throw the material upward is suppressed. However, when the lling machine is operating with pre-weighed charges, the head of material over the filling screw and its associated feeding impellers is usually initially somewhat low and diminishes rapidly as the charge is filled into a bag. Thus the centrifugal impeller type of the invention is better adapted for use where a substantial head of the material continuously exists and the modification of Figs. 17 and 18 is desirable where pre-weighed charges are to be filled.

As shown in Figs. 17 and 18, a main filling Also, the filling screw portion a axis of the main filling screw.

screw |69 is mounted within a casing ll, which tapers down to a reduced diameter as at 52. The filling screw let, of course, is reduced in diameter accordingly. The top portion of the screw casing, as at ldlc, is sloped downwardly from a point as at 52?) which is slightly above the upper reach of the filling screw, said casing portion lla sloping to a .point as at |520 which is closely adjacent the upper reaches of the filling screw, thereby defining a compression chamber |63 between said casing portion Mila and the screw |69.

A pair of packer screws me and |65 are mounted for rotation on opposite sides of and upon an axis transverse to that of said filling screw in such a manner that they feed directly into the main filling screw. In the form shown, the low point of the path of the screws 84, |65, as at llla and la, is substantially on the same level as the However, it is possible to lower further the screws itil and H65.

A pair of channel members, for respective of said packer screws is indicated as at |55 and |61. which channel members have rounded bottoms in which respective of such screws are rotatably mounted. The channel members |66, |37 have closed outer extremities at |660. and |6629, which extremities form a portion of a hopper for containing the material. The inner extremities of the channel members, that is, the ends thereof which are adjacent the filling screw |51), are of course open in order to permit the feeding of material to the main filling screw,

Although certain embodiments of the present invention have been illustrated and described which have given satisfactory results, it is to be expressly understood that the invention is not limited thereto, reference being had to the appended claims for the limitations of the invention.

What is claimed is:

l.. In apparatus of the class described, a filling screw trough having an outlet at one extremity thereof; a filling screw in said trough adapted for forcing material through said outlet; a centrifugal impeller having a plurality of blades and positioned adjacent said filling screw, the blades f of such impeller being movable into proximity with such filling screw for forcing material into the spaces between the screw surfaces of said filling screw, the axis of rotation of said impeller being transversely disposed relative to the axis of rotation of said filling screw; and subsidiary impeller means positioned on at least one side of said first-mentioned impeller and having impeller surfaces for urging material laterally into the spaces between the blades of said.

rst-mentioned impeller.

rial, a filling screw trough having an outlet; a nlling screw in said trough in alignment with the outlet for forcing material therethrough; a centrifugal impeller positioned with the axis of rotation therecf above and transversely disposed relative to said filling screw, said impeller having a plurality of blades which move lengthwise of said trough and pass in close proximity to said lling screw for forcing material into the spaces between the screw surfaces thereof; a filling tube protruding into said trough through said discharge opening and surrounding a portion of said filling screw, said filling tube protruding into said trough to a point substantially beneath such transversely disposed axis of rotation of said centrifugal impeller; and subsidiary impeller means positioned at least on one side of said first-mentioned impeller for urging material parallel to the direction of said transversely disposed axis of rotation and into the spaces between the blades of such first-mentioned impeller.

3. In apparatus of the class described, a casing having a discharge opening adjacent the bottom thereof, a filling screw in said casing in alignment with the discharge opening for forcing material therethrough, the width of said casing being substantially equal to the outer diameter of said filling screw; a centrifugal impeller having a plurality of blades which pass in close proximity to said filling screw for forcing material into the spaces between the screw surfaces thereof; a member interposed between said filling screw and said centrifugal propeller and extending from the discharge outlet substantially to the point where said blades come closest to said lilling screw; and subsidiary impeller means positioned beside said first-mentioned impeller and actuatable simultaneously therewith for forcing material laterally into the spaces between the blades thereof.

4. In apparatus of the class described, a trough, a filling tube for a valve bag, a filling screw partially in said trough, and partially in said tube for forcing material through the latter, a rotatable shaft mounted above and transversely disposed relative to said screw, a multi-blade impeller mounted on and rotatable with said shaft, a plane perpendicular to the axis of rotation of said impeller and passing substantially through the center of the blades thereof substantially containing the axis of rotation of said screw, a packer screw mounted on said shaft on one side of said impeller for feeding material towards the impeller, a packer screw mounted on said shaft upon the other side of said impeller also for feeding material toward said impeller, and a pair of troughs each mounted beneath respective of said packer screws.

5. In apparatus of the class described, the combination comprising: a filling tube for a valve bag; a filling tube trough mounted in alignment with said tube; a filling screw mounted in said trough and extending into said tube; a main feed trough mounted above and transversely of said filling screw trough, said main feed trough having a central opening; a multi-blade impeller mounted for rotation in said main feed trough, the blades of said impeller extending into said filling screw trough through said opening, the axis of rotation of said impeller being transverse to said lling screw and a plane perpendicular to such axis of rotation and containing the axis of rotation of said filling screw also passing through the blades of said impeller; a packer screw mounted upon one side of said impeller in said main feed trough for forcing material toward the impeller; another packer screw mounted in said main feed trough upon the other side of said impeller for forcing material thereto, and power means for rotating said filling screw, impeller and packer screws.

G. In apparatus of the class described, a filling tube for a valve bag; a filling screw trough in alignment with said filling tube; a filling screw mounted for rotation within said trough and extending partially into said tube; a multi-blade impeller mounted above said filling screw, the axis of rotation of said impeller being transverse to the axis of rotation of said filling screw; and right and leftl'iand packer screws mounted on opposite sides of said impeller for urging material toward said impeller.

7. In a filling apparatus the combination comprising a filling screw trough having an outlet; a filling screw in said trough in alignment with said outlet; a tube member in said trough for embracing a portion of said filling screw, said member being in communication with the outlet of said trough; an impeller having a plurality of paddles and mounted for movement into close proximity with said filling screw whereby material is forced into the exposed portion of said screw in said trough; and a pair of auxiliary screws mounted one on each side of said impeller for feeding material thereto.

8. In apparatus of the class described, the combination comprising; a righthand trough; a lefthand trough substantially co-axial with said righthand trough; a multi-blade impeller mounted between said troughs, the path of movement of the extremities of the blades thereof extending beneath said troughs; mechanism in said troughs for urging material between the blades of said impeller; a filling screw 'trough having an outlet and mounted beneath said impeller and transversely of the axis of rotation of the latter; a filling screw mounted in said filling screw trough beneath and outside of the path of movement of the extremities of said impeller blades, the latter passing into said filling trough and into proximity with said filling screw; and a filling tube in register with the outlet of said lling screw trough, said filling screw extending partially into said filling tube.

9. In apparatus of the class described, the combination comprising: a filling screw; a trough having a rounded bottom in which such filling screw is rotatable, there being an outlet at one extremity of said trough through which material can be forced by said iilling screw, the width of such trough being substantially equal to the outer diameter of said filling screw; a multi-blade centrifugal type impeller mounted f-or rotation adjacent said filling screw, said impeller being positioned with the axis of rotation thereof above and transversely disposed relative to said filling screw, the blades of such impeller being movable down into such trough for urging material substantially lengthwise thereof and down into the spaces between the screw surfaces of the filling screw; and subsidiary impeller means positioned at least on one side of said first-mentioned impeller for urging the material at one side of such first-mentioned impeller into the spaces between the blades thereof.

10. In apparatus of the class described, the combination comprising: a lling screw; a trough having a rounded bottom in which such filling screw is rotatable, there being an outlet at one extremity of said trough through which material can be forced by said filling screw, the width of such trough being substantially equal to the outer diameter of said filling screw; a multi-blade centrifugal type impeller mounted for rotation adjacent said filling screw, said impeller being positioned with the axis of rotation thereof above and transversely disposed relative to said filling screw, the blades of such impeller being movable down into such trough for urging material substantially lengthwise thereof and down into the spaces between the screw surfaces of the iilling screw, the blades of such impeller extending substantially tangentially with respect to the hub thereof, each blade having a tip member secured to the forward face thereof at its outer extremity; and subsidiary impeller means positioned at least on one side of said first-mentioned impeller for urging the material at one side of such first-mentioned impeller into the spaces between the blades thereof.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date Graumlch July 12, 1887 Holly July 14, 1916 Gregory Sept. 24, 1918 Kresnger May 1, 1928 Burger Nov. 13, 1928 Number 20 Name Date Marsh May 27, 1930 Marsh June 24, 1930 Currier Sept. 12, 1933 Marsh et a1 Aug. 18, 1936 Cundall Oct. 27, 1936 Harmon Aug. 20, 1940 Neill Oct. 21, 1941 McBean Apr. 6, 1943 Peterson Mar. 2, 1948 Stoker Apr. 10, 1951 

